The present invention relates to a fully automated patient interactive system for controlling neurostimulation, and more particularly, to a computer controlled system for automatic adjustment of neurostimulation implants used in pain therapy and in treating neurological dysfunction capable of automatically handling inconsistent patient data entries and unexpected conditions such as hardware failures.
Even more particularly, the present invention relates to a patient interactive system operated directly by the patient who may be safely and confidently left alone to work with the computer to obtain reliable data with the goal of maximizing pain relief while minimizing staff time demand. The novel system essentially replaces the physician, or physician""s assistant, in the routine and tedious task of adjusting stimulation settings for the neurostimulation procedure.
Moreover, the present invention relates to a patient interactive system comprising a patient interactive pentop tablet computer which may include an RF (radio frequency) interface device integrally built in the pentop tablet computer or in the antenna in combination with patient interactive software and allows signal communication with neurostimulation implants using radio frequency telemetry.
Additionally, the present invention relates to a patient interactive system for controlling neurostimulation which includes a unified user interface in which the body outlines and the patient""s drawings are input directly to the computer screen.
The present invention further relates to a patient interactive system having a xe2x80x9cuniversalxe2x80x9d transmitter for controlling implantable devices capable of imitating unique codes generated by proprietary neurostimulation systems thereby allowing the system of the present invention to work with a wide variety of implantable devices.
The present invention also relates to a method of controlling the neurostimulation in a neurological stimulation system for collecting data from a patient through a series of steps and further processing the collected data for optimization of the stimulus setting for the most effective pain relief and treatment.
Neurostimulators treat chronic pain by stimulating nerves, such as those of the spinal cord, with electrical pulses. Typically, neurostimulator systems comprise an external device which communicates with an implantable device through electromagnetic transmissions. The external device acts as a programmer for the implanted device by means of transmitting radio frequency codes to the implanted device to program its operation.
Neurostimulators have a number of parameters and adjustments that optimize the stimulation for each individual situation. Electrodes have multiple contacts that can have positive, negative, or off-polarity. Common configurations have 4, 8, or 16 electrode contacts within the stimulating bundle. Four electrodes can have 50 separate usable combinations of polarities. Eight electrodes can have 6050 separate usable combinations of polarities. Sixteen electrodes can have over 62,000,000 separate usable combinations of polarities. Beyond this, neurostimulators can set the frequency of stimulation between 1 Hz and 1500 Hz, set the pulse widths of stimulation between 10 and 1000 microseconds, and vary the amplitude of stimulation. These nearly inexhaustible adjustments quickly overwhelm the physical capabilities of medical staff to adjust stimulators through all settings for each patient.
To help with this concern, a computer-controlled neurological stimulation system, U.S. Pat. No. 5,370,672, was developed. The system provides efficient patient interaction, optimizes stimulation automatically, and delivers arbitrary and unique paradigms of stimulation. As shown in FIG. 1, an external transmitter 10 and implanted receiver 11 are RF coupled by an antenna 12. The external transmitter 10 is worn externally by the patient 13 to encode the stimulation parameters and the electrode selections, which are then transmitted to the implanted receiver 11 via the antenna 12. The implant decodes the transmitted information and generates the desired electrical pulses for stimulating electrodes 14 within the spinal column 15.
As shown in FIG. 2, the computer-controlled neurological stimulation system of the ""672 Patent includes a host computer 16, an interface enclosure 17 coupled by a cable 18 to the host computer 16, with an output line 19 coupled to an antenna 20. A graphic tablet 21 is connected by a serial line 22 to the host computer 16 which permits entry to the host computer 16 of the location of stimulation paresthesias and painful areas when a stylus 23 is manipulated over the tablet 21 by the patient. The tablet 21 has an overlay positioned on the top of the tablet 21 and contours of the body are drawn on the overlay. In operation, the physician initiates a session with the patient by calling up the appropriate programs in the host computer 16. The host computer 16 and interface enclosure 17 control one of several selective transmitters and cause the generation of various stimulation parameters such as frequency, pulse amplitude, width, and electrode combination. The patient at this time is directed via the graphics tablet 21 to interact with the host computer 16 and the interface enclosure 17 to adjust the stimulation amplitude as necessary and to sketch on the tablet 21 the areas of pain and the areas perceived by the patient to be experiencing paresthesias. While useful in reducing the workload of medical staff and automating the data collection, the system still has a number of limitations which include:
1. The patient has to look up to the monitor of the host computer 16 for instructions and then down at the graphics tablet 21 to draw responses and answers which presents a challenge in hand-eye coordination and slows data collection.
2. The overlay on the graphics tablet needs careful adjustment to accurately match its outlines of the body with the host computer""s internal representation of those outlines. This calibration is also necessary to match the drawings made by the patient which represent areas of pain and stimulation paresthesia with the host computer""s internal representation of the body.
3. The serial communications cable 18 between the host computer 16 and the transmitter enclosure 17 is prone to mechanical as well as electrical failure.
4. The patient is in physical contact with the transmitter interface enclosure 17 and the host computer 16, both of which are connected to electrical cords and wall outlets. These devices are powered by the building""s AC power and consequently have a grounded connection that can provide a leakage path or short circuit to ground.
Another patient interactive computer based neurostimulation system is described in U.S. Pat. No. 5,938,690. This system can assist in the performance of pre-, intra-, and post-operative procedures relating to the determination and optimization of a patient""s therapeutic regimen. The system is intended to record and process patient""s responses to test stimulation patterns during the operation of placing the electrodes, so as to give the physician real-time information that can be used to effectively position the electrodes within the patient""s body. The system also provides computer assisted post-operative presentation and assessment of stimulation settings.
Disadvantageously, the systems of prior art are not truly automated and require frequent attention by clinical staff during operation because either they do not provide automated patient interviews or their unsophisticated the electrodes and the transmitter.
It is therefore clear that despite the advances and improvements in prior art systems for controlling neurostimulators, a novel system which is automated and xe2x80x9cuniversalxe2x80x9d, i.e., compatible with a wide variety of different types of implantable devices is needed in the art of neurostimulation. interview schemes are unable to automatically handle inconsistent patient data entries and unexpected conditions such as hardware failures.
Another shortcoming of the prior art neurostimulation systems is that each manufacturer of implanted devices generally has proprietary codes built on combinations of the modulation techniques to program the implantable devices. Consequently, each manufacturer has proprietary hardware, software, and systems to transmit the programming code. If a separate external system other than one provided by a manufacturer of implantable devices, communicates with an implantable device, the external system requires circuitry that emulates the proprietary system. Should the external system communicate with multiple different types of implantable devices, it must include separate circuitry to emulate each type of implant. As an example, in the system described in U.S. Pat. No. 5,938,690, a physician enters into the computer information related to electrode type and transmitter type. Thus, the system requires the transmitter to xe2x80x9clearnxe2x80x9d certain stored information, ensuring that the transmitter, electrodes and the system in its entirety are compatible. In each operation, the transmitter must be reset with respect to electrodes it is supposed to work with, and the transmitter may have to be replaced with another type if the adaptation is not possible due to incompatibility of
It is therefore an object of the present invention to provide a truly automated patient interactive system in which provisions are made allowing for effectively handling inconsistent patient data entries, if any, and unexpected conditions such as hardware failures, thus providing that the patient may be safely and confidently left alone to work with the computer and where reliable data can be attained without significant intervention by a human clinician during the procedure.
It is another object of the present invention to provide a patient interactive system having a xe2x80x9cuniversal transmitterxe2x80x9d adaptable substantially to all types of implanted devices, including both RF-powered and implantable pulse generators (IPG) with self-contained power sources.
It is a further object of the present invention to provide a patient interactive system for controlling neurostimulation, in which the body outline, instructions for the patient, and the patient""s response are displayed and drawn on the same screen of the patient interface computer, thus avoiding hand-eye coordination problems.
It is another object of the present invention to provide a patient interactive system where the drawings are made by the patient directly on the computer screen, thereby making the data collection easier to use and speedier to collect.
It is still another object of the present invention to provide a patient interactive system having a unified structure which eliminates cables between various components, thereby greatly reducing possible mechanical and electrical failure.
It is still a further object of the present invention to provide a patient interactive system employing a battery-powered pen top computer thereby eliminating leakage paths and short circuits to ground.
It is yet another object of the present invention to provide a patient interactive system, a method for controlling neurostimulation, and software stored in the patient interactive computer to operate the system for data collection, data processing, and optimization of stimulation settings for a particular patient and his/her problem.
In accordance with the present invention, a patient interactive system for controlling neurostimulation includes a plurality of neurological stimulator devices implanted in the body of a patient, a patient interactive computer with a display, a transmitter interface unit integrally embedded within the patient interactive computer or built-in the antenna, a stylus movable by the patient in response to the request displayed on the display of the patient interactive computer, a physician""s desktop computer telemetrically communicating with the patient interactive computer, and operational software to run the system.
It is an essential and novel feature of the present invention that means are provided in the system which presets consistency boundaries for data entered by the patient and which verify that the entered data fall within the consistency boundaries. If the consistency boundaries are exceeded, then the data entered are recycled, and the patient is asked to repeat a response, or the system is checked for hardware failure. This arrangement in the system of the present invention provides for full automation of operation, obtaining of reliable data, and safety for the patient, so that he/she may be confidently left alone to work with the system without intervention by a clinician.
It is also important that the system of the present invention is capable of studying the consistency behavior of the patient, and, if satisfactory, to avoid verification as to whether the boundaries are exceeded, thus providing for adaptation to each particular patient.
The neurological stimulator devices are adapted for receiving a specific one of a plurality of predetermined programming codes and responding to this code to provide electrical stimulation to nerve tissue in accordance with the programming code. It is essential that the transmitter interface unit embedded within the patient interactive computer or the antenna unit includes controlling means which are adapted to imitate any one of a plurality of predetermined programming codes and drive the transmitter interface unit to transmit the imitated specific predetermined code toward the neurological stimulator device thus providing for universality of the transmitter.
The system includes graphic means displaying screen graphics and screen worded messages for the patient (the message corresponding to the screen graphics) substantially simultaneously on the display of the patient interactive computer. The screen worded message describes to the patient an action expected from the same to operate the stylus in order to enter requested data into the patient interactive computer.
The screen graphics may present images of a human""s body. Subsequently, the screen worded message requests the patient to outline, by means of the stylus, an area of the pain being experienced. The screen worded message may also request the patient to outline, by means of the stylus, a topography of paresthesias in response to electrical stimulation of the neurological stimulator devices by the specific predetermined programming code transmitted from the transmitter interface. The interior regions of graphical outlines may later be compared by the computer as part of the analysis to determine preferred stimulation settings. It is essential that the pain map and the topography of paresthesias are compared pixel by pixel rather than by any standard dermatomes in order to adapt the analysis accurately to the individual patient.
The screen graphics may also present a rating bar. The screen worded message constitutes a request for the patient to indicate on the rating bar (by means of the stylus) the degree of overlap of the area of the pain experienced and the topography of paresthesias.
Alternatively, the screen graphics may present a stimulation amplitude adjustment screen for threshold determination which includes an amplitude adjustment bar. In this mode the screen worded message requests the patient to increase the amplitude by sliding the stylus along the amplitude adjustment bar until the patient begins to feel a sensation that meets the stated criteria.
The system is capable of determination of a plurality of stimulation thresholds including the bilateral threshold, discomfort threshold, perceptual threshold, preferred level of pain relief threshold, area of interest threshold, and motor threshold. These parameters are further processed for obtaining an optimized stimulation setting for a particular patient and his/her problem.
Briefly, the present invention is directed to a computer controlled system for fully automatic adjustment of a neurostimulation implant used in pain therapy and in treating neurological dysfunctions. The system as herein described has been found to fill a void in modern healthcare technology. The system""s unique features dramatically decrease physician workload, increase productivity and increase efficiency of neurostimulators. The system is operated directly by the patient and substantially replaces the physician in the routine and tedious task of adjusting stimulation settings. The physician needs only to connect the patient to a patient interactive computer and select a protocol either on the physician""s desktop computer or on the patient interactive computer 25. Thorough records are compiled during adjustment sessions and this data along with the optimum setting analysis results are available for post session review by a clinician.
The patient interactive computer is preferably a pentop tablet computer often including a transmitter interface which allows it to communicate with neurostimulation implants using radio frequency telemetry. (In the alternative, the transmitter interface may be embedded in the antenna.) The patient interactive computer and/or the physician""s computer contain patient interactive software that has evolved out of extended periods of clinical research. The system may communicate using an infrared link with a printer for generating hard copy reports or with a desktop PC in the physician""s office for providing patient data. The patient interactive computer also may communicate with a remote computer server through a telephone line, to obtain value added services or software updates.
The transmitter interface includes:
a control interface unit communicating with the patient interactive computer to transmit data defining which one of a plurality of the predetermined programming codes has to be generated within the transmitter interface unit;
a data memory unit adapted to store a plurality of parameters for the multiplicity of specific predetermined programming codes;
a direct digital synthesizer interfacing with the control interface unit and receiving data from it;
a programmable clock unit interfacing with the control interface unit and receiving data therefrom for clocking the direct digital synthesizer;
a programmable gain/amplitude control unit interfacing with the control interface unit and receiving data from it; and
a radio frequency amplifier coupled to an output of the direct digital synthesizer and amplifying an output signal received therefrom to be transmitted to the neurological stimulator device.
An alternative embodiment to the use of a radio frequency amplifier which in certain instances may not be an efficient method of driving the antenna, an alternative approach is taken for the transmitter interface unit. In the alternative embodiment, the transmitter interface unit comprises a control interface unit communicating with the patient interactive computer to interchange the data defined by the processing means of the patient interactive computer. A data memory system is adapted to store a plurality of parameters for the proprietary programming codes. Further a direct digital synthesizer (DDS) interfacing with the control interface unit for receiving data therefrom and outputting a carrier signal in response thereto is provided. A transistor circuitry is operatively coupled to the antenna for driving the antenna in on/off fashion. Finally a driving unit interfacing with the direct digital synthesizer is provided for generating gating pulses supplied to the transistor circuitry to drive such in a manner defined by the processing means within the patient interactive computer.
The driving unit may include either an analog comparator receiving at one input thereof the carrier signal (in analog form) from the DDS and comparing the carrier signal with a reference signal supplied to another input of the analog comparator. Alternatively, the driving unit includes a digital comparator receiving at one input thereof a carrier signal (in digital form) from the DDS and comparing the carrier signal to a reference code which is indicative of the width of a gating pulse to be output from the comparator. The output of the comparator (either digital or analog) is coupled to the transistor circuitry which in turn, drives the antenna.
Preferably, the transistor circuitry is an H-bridge which may include multiple inputs independently driven by the driving unit. Several implementations of the H-bridge circuit are contemplated in the scope of the present invention. In order to drive inputs of the H-bridge circuit independently, either multiple comparators are employed in the universal transmitter, or a single comparator with multiple outputs is used to supply gating control signals to the respective inputs of the H-bridge circuit.
In another alternative embodiment, the universal transmitter interface unit includes a balanced modulator for modulating the carrier signal. In this implementation, a combination of analog and digital techniques is used to provide a flexible and versatile modulation of the carrier signal generated at the digital direct synthesizer. In this embodiment, the transmitter interface unit further includes a low pass filter coupled between the output of the digital-to-analog converter (DAC) of the direct digital synthesizer and a first input of the modulator unit. A digital comparator having first and second inputs and coupled by the first input thereof to the output of the phase accumulator of the direct digital synthesizer and by the second input thereof to the control interface unit is included. A switching mechanism is incorporated for intermittently connecting a second input of the modulator unit to the output of the digital comparator and an output of the control interface unit.
In operation, a physician enters information about a patient into the system through either the physician""s desktop computer or the patient interactive computers and chooses an optimization protocol from the available menu of the protocols. The patient interactive computer is then left in the hands of the patient for a fully automated session for the chosen optimization protocol.
A typical stimulation session involves a repeated cycle through the following steps:
1. Patient interactive computer automatically sets implant stimulation parameters;
2. Patient adjusts amplitude to meet one or more predefined criteria thresholds;
3. Patient draws area of stimulation coverage on a body outline;
4. Patient rates effectiveness of the setting on a 100 mm scale;
5. Patient interactive computer turns off stimulation and waits for stimulation sensation to clear;
6. Process proceeds again with a new stimulation setting until the session is finished.
The menu of optimization protocols referred to as testing/procedures before the data analysis may include the following operations in a predetermined combination thereof for a specific testing procedure:
1. A patient controlled amplitude adjustment procedure allowing the patient to adjust stimulation level to meet amplitude threshold;
2. Entry of an area of the pain experienced overlapped with an image of a human""s body displayed on the display of the patient interactive computer;
3. Entry of a topography of paresthesias in response to the electrical stimulation overlapped with the image of the human""s body displayed on the display of the patient interactive computer;
4. Entry of data corresponding to a degree of overlapping of the area of the pain experienced and the topography of paresthesias;
5. Establishing a pause between switching from one protocol to another;
6. Determination of xe2x80x98multiple thresholdsxe2x80x99.
For example, a bilateral optimization protocol would include collecting data from amplitude adjustment procedure (operation #1), collecting drawings (operations #2-4), collecting data related to patient ratings for the bilateral threshold with stimulation parameter selected in some particular fashion (operation #6). In some cases, the software allows a multi-level body-region entry by sequentially entering previous and successive measures of identical nature with reference to the image of the body displayed on the display of the patient interactive computer with the body-regions previously drawn displayed for the reference.
Preferably, when data entered fails to be consistent with expected or estimated data the patient is requested to redo the entry procedure.
Data collected for each stimulation setting is compared against data for other settings and against the previously entered pain drawing. A list of best settings is produced and sorted in rank order by the physician chosen criteria. The best settings may be printed in report format or they may be programmed automatically into an advanced patient stimulator as xe2x80x9cpresetsxe2x80x9d, which present stimulation prescriptions that the patient may select electronically (the selection of a xe2x80x9cpre-setxe2x80x9d may be done even if the patient is not in the clinician""s office).
The collected data may be transferred between many patient interactive computers. The data may be re-analyzed or used as the basis for further patient testing on other patient interactive computers, or it may be simply stored in a common data base for the center. Patient data and implant information can be transferred to remote data servers.
These and other novel features and advantages of this invention will be fully understood from the following Detailed Description and the accompanying Drawings.